Warning aired on use of QT bars for buildings

CLARK FREEPORT, Pampanga, Philippines — Former senator Nikki Coseteng has expressed concern for the safety and lives of Metro Manila folk residing or working in high-rises built in the last 10 years amid the possibility that the skyscrapers would not withstand a major earthquake in the metropolis.

In a recent forum at the Park Inn hotel here, Coseteng cited a study by structural engineer Emilio Morales who noted that in the past decade, contractors of high-rise buildings in the country have been inadvertently using quench-tempered reinforcement steel bars (QT rebars) instead of the stronger micro-alloyed or MA rebars.

Morales, who was in the forum, said, “advanced countries have warned against these dangers and we believe it is our duty to inform the public and the profession of their use in Seismic Zone 4 (Metro Manila).”

Earlier, the Philippine Institute of Volcanology and Seismology (Phivolcs) warned that active faults underneath Metro Manila could trigger a 7.2 magnitude earthquake anytime that could lead to massive devastation.

Morales cited engineering studies in Italy, New Zealand and other countries backing his claim that QT bars are not for high-rise buildings.

“One cycle of significant earthquake, which refers to merely one movement of earth from one side to another, is enough to damage a QT rebar’s outer layer. Eventually, the impact would be passed on to the concrete,” he said.

Morales said, however, that most contractors for high-rise structures were apparently not informed by suppliers about the rebars delivered to them, as most contractors merely seek grade 60 rebars without specifying whether they were QT or MA. While both are grade 60, MA rebars are stronger inside the pith, while only the outer layer of QT rebars is strong enough.

Palace undersecretary for disaster resiliency Karen Jimeno said that suppliers of QT rebars could be held criminally liable as contractors were not fully informed of the quality of steel materials being delivered.

Meanwhile, the Department of Public Works and Highways (DPWH) is set to present to Congress its final proposal for a Philippine Building Act to replace the 1977 National Building Code, based on the government’s duty to “safeguard the life, health, property and public welfare consistent with principles of sustainable development” amid disaster risks.

In a recent press forum, Jimeno, former DPWH undersecretary, said the proposal was also based on the United Nations framework for disaster risk reduction for 2017 to 2030, as finalized in Sendai, Japan in March 2015. 

Jimeno noted that the Sendai framework aimed to “substantially reduce global disaster mortality (and) the number of affected people, reduce direct economic loss in relation to global gross domestic product, substantially reduce disaster damage to critical infrastructure and disruption of basic services.” 

Under the proposed Philippine Building Act, prescribed quality of buildings is detailed, the  list of those tasked to ensure the quality and safety of buildings is longer  and penalties for violators are stiffer.